US, WASHINGTON (ORDO NEWS) — The U.S. Air Force is expected to launch its secret X-37B spacecraft for a long mission in low Earth orbit. The robotic orbiter looks like a smaller version of the space shuttle. He spent nearly eight of the last 10 years in space, conducting secret experiments for the military. Almost nothing is known about what the X-37B is doing there, but before its sixth launch, the Air Force presented some rare details about its cargo.
In addition to its usual set of secret military technology, the X-37B will also conduct several unclassified experiments during its upcoming stint in space. NASA is conducting two experiments to study the effects of radiation on seeds, and the U.S. Air Force Academy uses a space plane to deploy a small research satellite. But the real star of the program is a small solar panel developed by physicists from the Naval Research Laboratory, which will be used to conduct the first orbital experiment with space solar energy.
“This is a major step forward,” said Paul Jaffe, an electronics engineer at the Naval Research Laboratory and lead researcher for the project. “This is the first time a component designed for a solar-powered satellite system will be tested in orbit.”
Cosmic solar energy is the transfer of solar energy to the Earth, regardless of weather or time of day. The main idea is to convert the energy of the sun into microwaves and direct it down. Unlike ground-based solar panels, satellites in high enough orbits can only be in the dark for several minutes a day. If this energy could be captured, it could provide an inexhaustible source of energy, no matter where you are on the planet.
This is an idea invented by science fiction writer Isaac Asimov in the 1940s. Since then, experiments with radiation energy have been successfully tested on Earth several times. But the experiment on the X-37B will be the first when the core technologies underlying microwave solar energy are tested in orbit.
“The science of microwave radiation of energy is fully understood; it is engineering problems associated with scaling known technologies to sizes never before seen in orbit that need to evolve, ”said Jan Cash, director of International Electric Company Limited, which is developing a space solar platform called CASSIOPeiA. “But every undertaking must begin with the first step.”
The experiment built by Jaffe and his NRL colleagues is what he calls the “sandwich” module. This is a three-level system for converting sunlight into electricity, and then converting electricity into microwaves. Typically, a conversion system is located between a high-performance solar panel and an antenna that is used to transmit energy. But in this mission, Jaffe and his colleagues will not radiate energy from space to Earth, because the radio signal will interfere with other experiments in orbit. Instead, the sandwich module will send radio signals over the cable so that NRL researchers can examine the system’s output power.
The entire NRL experiment can fit in a pizza box and will not provide enough energy even to power a light bulb. But Jaffe says the experiment is a critical step towards a free space satellite. “There was a lot of work to study and analyze, and much less work to actually prototype,” says Jaffe. “This is not necessarily the most sophisticated version of what can be achieved, but the main goal was to go up into space with proof of this concept.”
Jaffe has been working on space solar energy at NRL for over 10 years and first introduced his prototype sandwich module in 2014. This project was supposed to solve a number of problems that have pursued space research on solar energy for many years. One of the biggest problems is that in-orbit solar panels must be massive to collect enough sunlight to be useful for Earth applications. Even if these structures could be built in principle, they would be incredibly expensive and difficult to run.
“It would be too big and cumbersome to run this complete system,” says Chris DePuma, NRL Electronics Engineer and Experiment Program Manager. “A sandwich module is a way to reduce the mass and modularity of a system so that it can be assembled in orbit.” But before the robots begin to build giant solar farms in space, there are a number of fundamental problems with the panels themselves that need to be addressed.
Jaffe says one of the biggest challenges is temperature control. In space, a solar panel facing the sun can reach temperatures of up to 150 degrees Celsius, while electronics directed away from it should work at a temperature several degrees above absolute zero. This electronics is only a few centimeters apart, so Jaffe and his colleagues had to figure out how to adapt to both extremes. Jaffe says that this is mainly due to replacing materials and modifying the design of the module so that the solar panel is isolated from electronics that works better at lower temperatures. The upcoming X-37B mission will test this version of the sandwich module.
Flying in a secret air force spacecraft was accompanied by some compromises. If such an experiment were conducted on a satellite, it would be placed in orbit, where sunlight would almost always be available. But the X-37B will fly in low Earth orbit, which means that it will pass through the shadow of the planet about every 90 minutes. Nevertheless, the benefits of this spacecraft flight are worth the trade-offs. “We need to focus more on our experiment, and not on the development of the propulsion system and everything else that the satellite has,” he says. “The device will simply collect our data and send them to us in the form of results.”
If all goes well, Jaffe says, the next step will be to develop an experimental space satellite to receive solar energy and transfer energy from orbit to Earth. He acknowledged that this would require convincing the Department of Defense that time and money were worth the effort. But the military is clearly interested in technology. Last October, the Air Force Research Laboratory announced a $ 100 million program to develop solar-powered satellite equipment.
Jaffe sees the use of cosmic solar energy, initially allowing it to be used for drones that should never land, or to power remote military bases around the clock. But he sees even bigger things for this technology. “Space solar energy is solving the biggest problem of scaling existing ground-based renewable energy sources, namely storage,” he says. “With the significant cost savings that the reusable space launch will give, space solar energy could very well become the cheapest source of continuous carbon-free energy.”
Jaffe loves comparing the cosmic concept of solar energy with GPS. If you told someone a few decades ago that a network of satellites loaded with an atomic clock would become the pillar of modern society, they would think that you were crazy. But today, GPS does everything from sharing services to nuclear warheads. In fact, many of its most important applications were not even designed when the first GPS satellite was launched. Jaffe believes that the same may be true for cosmic solar energy. The transfer of solar energy from space to Earth sounds extravagant, esoteric and impossible – as long as this is not so.
Contact us: [email protected]